That's weird. "Overfilled" really isn't even possible unless the whole system was filled in some pressure chamber and even if that was the case the overfilled state would let it never fully engage. It would still fully disengage though allowing you to shift. Ride it for a week and report back. Im curious if it really did fix this issue. It shouldn't do a damn thing but I hope it does for you!
Emoto; Thanks for the tip ! Just checked my bike and as yours it was overfilled as well. Thanks to your pictures I was prepared and had put an rag to catch any excess fluid so it wouldn't drip on the bike. In fact my spilled more than yours... EJ92606; There is no sight glass on the clutch reservoir; I saw no internal level markings. I left mine at mid level as the top cover has a rubber part that goes quite inside this reservoir and tends to bring the level up considerably once it is closed. oz97ti; ALthough I agree that there is no way to overfill this reservoir, it seems to me that there might be some sort of "back pressure" form the clutch or lower piston that pumps the fluid back to this reservoir. If this "overfilling" affects the clutch performance I don't know, however, it doesn't seem reasonable to me that there was so much fluid in there so I took some out. I haven't ridden my bike since I did this to see if I it gets easier to find "neutral" which is my only difficulty, I will report back as soon as I try it out. Andre
I don't know how they fill them when building the bikes. What I can say with absolute certainty is that resetting the amount of fluid to a normal level had a very definite and pronounced effect. It was obviously different. There was no thinking about it and turning it over in my mind trying to determine if there had maybe been some minor change. No, it was a big change that was immediately apparent. Of course, I will keep an eye on it and will report back if something untoward happens, but if I had to bet, I would bet that this settles the matter. EJ, I just filled the reservoir half way up.
As promissed I am reporting back: I went for a ride and must say I am IMPRESSED ate the improvement !!! After a while I started to count how many times I put the bike from 1st into neutral at stoplights. On about 60 counts, it went smooooooothly 52 times, of the other 8, 5 times the lever was a bit harder but went into neutral. The remaining 3 it went staright into second gear. Overall I would say it was a 20 to 30% improovement. I also found out that on the occasions when the lever becomes hard to pull up, a gas blip ( up to some 3K rpm ) makes it go smoothly into neutral. Overall I find these statistics quite similar from what I recall my 3 previous GSs were. To say I am really happy with these results is the understatement of the year ! Thanks for really GREAT tip !!! Andre
Huh..seems like something easy to try and I shall! Thanks for posting this..will report early next week on how it goes after a couple of days
My dealer is both car and bike BMW dealer... The service advisor once told me some items are intentionally not bulletproof to keep customers coming back to the dealership. It didn't really make sense to me. What brought it up was a failed high pressure fuel pump that was a known issue for a long time before BMW had to recall and extend warranty. Years went by with them just replacing the part and not really addressing a fix. my last car upgrade did happen as I was using a loaner car ... On a routine service call. I simply had to have that turbo BMW ... It still doesn't make sense for new vehicles to have these nuisance items installed.
Think of the fluid, including that in the m/c, as a long rod used to push the slave cylinder. That rod must be free to move back and forth. With the whole system entirely full, its movement is inhibited.
Right. But this would lead to the clutch not being fully engaged which would cause slip. This would also allow the clutch to fully disengage as intended when the lever is pulled. Lowering the fluid level could alleviate a slipping issue but your issue was rough shifting which would indicate the clutch wasn't disengaging which is backwards to what too much fluid would cause. :huh
A lot of items have a weak link designed to fail before a larger more expensive part fails. Back before stepper motors, many office machines used chains with plastic gears that would strip. If this was not designed into the product and a bearing froze it could bend a frame. This happened many times do to incompatible lubricants, lack of lubricants, or parts that were run past there life span.
On the clutch master cylinder issue, I think there is some confusion about what the master cylinder reservoir does. The reservoir is a holding tank to provide additional fluid to the system as the brake pads wear. It is not pressurized. You can confirm this by noting that you can actuate the clutch with the cover off the reservoir and it will work fine. As someone else said, it doesn't make much sense that the level in the reservoir makes any difference - it could be chock full or almost empty and the action of the clutch should be completely unchanged. That being said, maybe there is something weird going on - strange interactions do happen. - Mark
There is one user in the German GS forum who just got his bike back from the dealer. He states that he was told that BMW is officially aware of a clutch problem now. They admit there is something wrong and they are working on a solution. The issue they named is (hope I get that right in English) the pressure plate and pressure pin of the clutch. Nevertheless, I also decreased the amount of fluid in the clutch reservoir and observed an improvement! I didn't take an fluid out, I just let the redundant fluid ran out on it's self! The issue is not solved with that measure but it's definitely for what ever reason compensated until a proper solution will take place.
The main point of any hydraulic fluid is that you cannot compress it. So, whe the reservoir is so full that the fluid bursts out when you crack the top, then "there is no room at the inn" so to speak, and therefore the whole system is virtually locked up. This makes for odd behavior. I am (so far, anyway) unfamiliar with the details of the inner workings of the clutch mechanism and slave cylinder of this bike, so I cannot walk us through the step-by-step, but given that we have empirical evidence, there has to be something about it that allows the system to work better. I did about 180 miles of mixed highway and backroads riding today in 90 degree heat, and it confirmed my impression from yesterday that shifting was much improved.
There is a bladder in the reservoir that allows for pressure difference. It'll also push any "extra" fluid out when the lid is cracked open. As you stated in an earlier post, the system is probably filled through the bleeder so the bladder would be compressed some. This would account for the overflow you had when opened the lid. You're also right about the fluid not being able to be compressed. That's my point I'm trying to make. If the system truly was overfilled, then it would ultimately be acting the same as having the lever pulled in slightly which would case slip. Thats the whole point of this. The hydro system is a very basic system. Thats why this really doesn't make any sense. We can talk about how the clutch works all day, but the system remains the same.
So, what you are saying is that there is no typically BMW quirky aspect to anything in the design of the system? I have had plenty of clutches and slave cylinders apart, but not a BMW and not one of these, so I am more than a little reluctant to make assumptions. If we were talking about Yamaha, Suzuki or Honda, I could go along, but until I can see a service manual or have my hands on actual parts, I just don't know. Sure, on a surface level I get your point, but what has BMW done with the slipper aspect? And what else have they designed in? I don't know.
I just did; mine was filled about the 90% point, maybe 95%, but not "pressurized". I have some erratic shifting, mostly fine, sometimes not. If not for all the discussion here I'd probably even not notice or give it a thought.
The slipper clutch doesn't have anything to do with the hydro system. As for the BMW special setup, you may have a point, but it appears its all "normal." Clearly your issue is fixed, but I just don't understand why and I'm really curious. I really can't grasp how LOWERING the fluid would help your issue.